Mordant and method of making same



Patented Dec. 12, 1939 2,183,390 MormaN'r AND. METHOD or MAKING SAME Harold E. Bode, Chicago, -Ill., assignor, by mesne assignments, to Corn Products Refining Company, New York, N. Y., a corporation of New Jersey No Drawing. Applicationseptember 20, 1937, Serial No. 164,797

8 Claims.

I This application relates to the dyeing' art and, more specifically, to the production of an improved mordantwhich is particularly adapted for use in the textile industry.

5 Metallic oxides have heretofore been extensively employed in the dyeing industry because of their ability to fix colors. For example, certain dyestuffs, which are of little or no 'value when employed alone because they do not penetrate fibres, are of primary importance in the dyeing" industry due to the fact that they act like weak acids and combine with metallic oxides to form insoluble colored compounds termed lakes which vary in color according to the metallic oxide employed. The colors thusformed within and about fibres are exceedingly fast to light, y washing and other influences.

1 The 'mordanting operation may be effected as a preliminary operation in which the textile to be 20 dyed is treated with the metallic oxide before the j dyestufi is added or during or after the dyeing operation. However, at whatever stage of the operation the metallic oxide is brought into contact with the dyestuff, the common practice'is to :25 chemically precipitate the insoluble metallic 0xide, usually as a hydroxide, from a solution of L the metallic salt so that the oxide is uniformly suspended in the bath as a finely divided colloid, in which form it is more readily distributed 30 through and deposited on the textile fibres.

The present invention is not concerned with any particular method or type of dyeing nor with any particular .dyestuff but rather with the production of animproved mordant product which i 35 is of general utility in the dyeing and textile printing art.

The present invention contemplates, in brief. the economical production of an intimate blend of the metallic oxide with starch, to provide a 40 mordant which is readily available without preliminary transformation and which possesses other superior qualities.

Starch, by itself, is widely used in the textile industry for sizing and stiffening cloth. It serves 45 to bindtogether and strengthen the fibres and to add weight to the textile product. mixed with filler material because of its ability to prevent dusting out of the filler and to impart a gloss to the cloth if the latter is calendered. In 50 the textile printing art it has been used in the form of a starch paste to increase the viscosity of mordant or color solutions to such a degree that any running is prevented and a sharply defined impression is obtained when the colors are printed 55 on the cloth. Similarly, starch paste has been It is also compounded with reagents to provide a combination with the pasted starch of certain metals or com ounds thereof "whereby, among other ad- I vantageous uses for which the products may .be

employed, certain pure colors may be obtained. However, with any such process the pasting or gelatinizing of the starch not only changes the identity and characteristics of the starch but also the dry product canbe obtained only by comparatively cumbersome, difiicult and expensive methods. Starch is also employed in certain industries for its penetrating ability. r

The mechanical mixing of starch and a mordant material is not satisfactory for the reason that it is of primary importance that the mixture be sufficiently uniform to obtain the desired results. If the textile being treated is'not thoroughly impregnated with thernordant some of the dye will wash out when the material is cleaned. Furthermore, the mixing operation .is

attended by commercial disadvantages in that it involves both time and expense at the dyeing plant. For commercial expediency the starch Q.

must necessarily be purchased in'a dry state and then suspended in the desired solution by prolonged agitation and with the exerciseof great care that the starch is not'delet'eriously afiected by the other ingredients of the solution.

One of the objects of the present invention is to provide a mordant'comprlsing a blend of' ungelatinized starch and a metallic oxide in which the ingredients are intermixed with substantially perfect uniformity.

Another object is to provide an improved mordant which can be marketed in a dry state and is readily available for immediate use Without any chemical pre-treatment.

Another object of the present invention is to provide a relatively simple and economical method for producing a mordant of the typehereinabove briefly described.

A further object is to provide an improved mordant product possessing improved penetrating powers.

These and other objects will be fully apparent from the following detailed description.

According to the present invention I precipitate the insoluble metallic oxide in a water suspension of ungelatinized starch,- whereby the finely. suspended precipitate is attracted to and deposited on the starch granules by ionic adsorption, thus yielding, by proper control of the relative concentrations of the starch and metallic oxides, a virtually perfect blend such as could not be obtained by mechanical mixing of the two sub- 66 stances. The mixture is then filtered, washed and dried and the resultant product is ready for use.

Any relatively insoluble metallic oxide may be used, such as aluminum, chromium, tin, iron, copper, magnesium, etc., although chromic hydroxide (Cr(OH)3) is perhaps the most satisfactory for this purpose. Precipitation may be accomplished in any known manner, for example, by dissolving into the starch suspension a soluble salt of the desired metal and using an alkaline hydroxide or carbonate or ammonia as a precipitant. The relative amounts of starch and hydrous oxides may vary considerably but, for general purposes, the amounts should be substantially equal so as to obtain a perfect blend.

The following example illustrates one embodiment oithe present invention as applied specifically to aluminum hydroxide, which is taken as an example for the reason that in precipitating aluminum hydroxide an incremental addition of ingredients is necessary. This precaution need not be taken when precipitating chromic hydroxide, for example.

Example To a water suspension of starch consisting of 10 parts starch and parts water, add, in small increments, 14 parts of aluminum chloride and 13 parts of sodium hydroxide. The addition of the aluminum chloride and the sodium hydroxide in small increments is necessary in order to avoid gelatinization of the starch by the sodium hydroxide or by the aluminum chloride, the latter of which evolves considerable heat upon dissolving in water. By means of individual increment additions the added ingredients are transformed to an aluminum hydroxide precipitate and sodium chloride before sulficient reaction takes place to gelatinize the starch. The entire process should, of course, be carried on at temperatures below the gelatinizing temperature of starch.

The aluminum hydroxide precipitates in the form of finely suspended, positively charged colloid particles which are immediately attracted to and deposited on the colloidal starch particles which are negatively charged.

During 'iis operation the mixture is constantly agitat to prevent settling out and to insure uniform ribution of all of the colloid particles and also keep the sodium chloride in solution.

After the last increment of the aluminum chloride and sodium hydroxide is added, the mixture is then filtered and the solid material washed and dried.

Fee resulting product can be utilized directly by the textile manufacturer without the necessityof first starting with the soluble metal salt and then precipitating out the insoluble colloidal oxide. The presence of the starch in such an intimate blend with the oxide presents several distinct advantages, notable among them being increased penetrating powers of the mordant product and uniform dispersion of the metallic oxide. Also, as hereinabove mentioned, the presence of the starch in the finished product is of value in certain cases because of its sizing properties.

From an economical standpoint, the present invention has advantages both to the starch manufacturer and the dyer for the reason that the latter is freed from the precipitating operation and the expense and trouble incident thereto and the former, the starch manufacturer, can

utilize, in the manufacture or the product, a starch suspension taken directly from the wet starch manufacturing process.

The above example is, of course, merely illustrative. The invention is not limited to the oxide of any particular metal nor to any particular method of precipitating the oxide, as many such methods are known and can be utilized to advantage in carrying out the present invention. As will be readily apparent to those skilled in the art, the product is adaptable for use in various known dyeing and textile printing operations and other ingredients such as fillers, etc., may be added to the product either during or after its manufacture. The particulanoxide (or combination of oxides) to be used for any given dyeing operation will depend, to some extent, on the color or colors to be employed. For example, an aluminum mordant is particularly suitable for red and pink color lakes; an iron mordant, purples and lavenders; chromium, maroons; and-mixtures of iron and aluminum, various tones of chocolate and brown.

It is the intention to cover all modifications or variations falling within the scope of the following claims:

I claim:

1. A mordant comprising a physico-chemical blend of ungelatinized starch and a water-insoluble, metallic oxide.

2. A mordant comprising a physico-chemical mixture of substantially 50% by weight ungelatinized starch and 50% by weight, a water-insoluble metallic oxide. I

3. Method of making a mordant product which comprises precipitating a water insoluble metallic salt in a watersuspension of starch in the absence of a starch gelatinizing temperature.

4. Method of making a mordant product which comprises precipitating a water insoluble metallic oxide in a water suspension of starch in the absence'of a starch gelatinizing temperature.

5. Method of making a mordant product which comprises adding to a water suspension of starch in the absence of a starch gelatinizing temperature a soluble metallic salt and an agent to precipitate out the water-insoluble oxide of said metal.

6. Method of making a mordant product which comprises adding to a water suspension of starch in the absence of a starch gelatinizing tempera- 7. Method of making a mordant product which comprises slowly adding to a cold water suspension of starch containing substantially 10 parts starch and 100 parts water, substantially 14 parts aluminum chloride and 13 parts sodium hydroxide, filtering and washing and drying the resulting solids.

8. Method of making a mordant product which comprises precipitating an insoluble metallic oxide in a water suspension of ungelatinized starch, while agitating the suspension and maintaining temperatures below the gelatinizing temperature of starch, whereby the finely divided precipitate is attracted to and deposited on the starch granules by ionic adsorption; then filtering out the solids and washing and drying the same.

HAROLD E. BODE. 

